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In the October 12 issue of the New England Journal of Medicine, Dr. Moore and his colleagues presented the results of their groundbreaking study, which represents a collaboration of researchers from the Imperial College London, the Johns Hopkins Bloomberg School of Public Health, and Peru's Universidad Peruana Cayetano Heredia. The product of their research, the MODS test, is based on a novel method of culturing M. tuberculosis in a liquid medium rather than on a conventional solid substrate. This new technique encourages faster bacterial proliferation and makes it easier to observe the bacteria under a microscope. Antibiotics also may be added directly to the liquid culture, allowing more rapid, extensive drug susceptibility testing.

To test the clinical viability of the new MODS test, the researchers collected nearly 4,000 sputum samples from patients in clinics and hospitals in Lima, Peru over a period of two years. The samples were then subjected to MODS testing as well as to two current gold-standard tests: the Lowenstein-Jensen culture and the automated mycobacterial culture. The results of this comparative study are encouraging: the sensitivity of the MODS test in detecting TB is 97.8%, as compared to 84 percent and 89 percent for the two other tests, respectively. Moreover, the MODS test allows researchers to diagnose TB twice as quickly as current tests and to identify MDRTB strains in one-third of the time, yielding results in about seven days. The MODS test has significant applications in cases of MDRTB combined with HIV infection, allowing more prompt, accurate diagnosis in immunodeficient individuals.

Professor Peter Davies, secretary of the group TB Alert, commented: "This is a very exciting development, which offers the best hope of a quick diagnosis for the 50 percent of people in the developing world who are not detected by the current [sputum smear microscopy] test." Dr. Moore also hopes that the MODS test will help to "bring equity in TB diagnostics to countries with limited resources, where the need is greatest." Indeed, the accuracy and relative simplicity of the test, in addition to its cost efficacy, make this new tool optimal for implementation in developing countries and poorer urban settings.

At present, Dr. Moore and Professor Jon Friedland of the Wellcome Trust Center for Clinical Tropical Medicine at the Imperial College London are assessing MODS test implementation in two southern Peruvian cities. They note that the test requires trained technicians and appropriate biosecure facilities, but that training requires only ten days, facilitating the introduction of MODS testing in developing countries. The researchers also report that they "have plans with a range of potential willing collaborators in Africa and Asia to rollout MODS in a number of different settings over the next six months."

Michaela Panter is a senior Biomedical Engineering major at Yale University. She is a Senior Editor for P.H.